In the fields of the production of semiconductor devices, liquid crystal displays, printing plates, bumps and magnetic heads, for example, there have hitherto been used a photoresist compositions for g-rays, h-rays and i-rays, comprising an alkali soluble resin and a quinonediazido group-containing compound (photoactive compound: PAC) as a main component; and chemical amplification type photoresist compositions for radiation such as i-rays, KrF, ArF and electron beam, comprising an acid dissociable group-containing compound (resin) and a photo acid generator (PAG) as a main component.
Examples of the chemical amplification type photoresist composition include those described in the following Patent Documents 1 to 3.
Patent Document 1 describes a composition comprising a linear polymer having an acid component and a hydroxyl group, PAG and a compound having at least two specific enol ether groups, the linear polymer and the specific compound being crosslinked by heating.
Patent Document 2 describes a composition comprising a linear polymer having an acid group, PAG and a compound having at least two specific enol ether groups, the linear polymer and the specific compound being crosslinked by heating.
Patent Document 3 describes a composition comprising a partially crosslinked polymer, which is obtained by reacting a hydroxyl group-containing polymer with polyvinyl ether in the presence of an acid catalyst, and PAG.    (Patent Document 1) Japanese Patent Application, First Publication No. Hei 6-148889    (Patent Document 2) Japanese Patent Application, First Publication No. Hei 6-230574    (Patent Document 3) Published Japanese Translation No. 2002-529552 of the PCT Application.
Recently, the integration degree of semiconductor devices has increased more and more.
Various proposals have hitherto been made on chemical amplification type resists which contribute to improvement in integration degree of semiconductor devices.
In the following Patent Document 4, there is described a two-component resist comprising a base material resin wherein hydrogen of hydroxyl groups of polyhydroxystyrene having high transparency to a KrF excimer laser beam is substituted with an acid dissociable alkali dissolution inhibiting group, for example, tertiary alkyloxycarbonyl group such as t-boc (tert-butoxycarbonyl) group or acetal group such as 1-ethoxyethyl group, and a photo acid generator as a main component.
A summary of the principle of the resist pattern formation in the resist proposed in Patent Document 4 is as follows. That is, since the base material resin has an alkali dissolution inhibiting group such as t-boc group, alkali solubility is inferior to polyhydroxystyrene having no t-boc group. When such a resin is mixed with a photo acid generator and the mixture is selectively exposed, the t-boc group is dissociated by an action of an acid generated from a photo acid generator at the exposed area to produce polyhydroxystyrene, and thus the resin becomes alkali soluble.    (Patent Document 4) Japanese Patent Application, First Publication No. Hei 4-211258    (Patent Document 5) Japanese Patent Application, First Publication No. Hei 10-268508    (Patent Document 6) Japanese Patent Application, First Publication No. 2003-167357